To measure the resonant cavity’s loaded Q-Factor we simply use our Agilent FieldFox Vector Network Analyzer (VNA)’s S11 return loss function to determine the bandwidth of the resonant cavity’s -3.0 db points from the 0.0 dB reference, divide this bandwidth figure by the resonant frequency and then invert that number to get the loaded Q-Factor

To measure the resonant cavity’s loaded Q-Factor we simply use our Agilent FieldFox Vector Network Analyzer (VNA)’s S11 return loss function to determine the bandwidth of the resonant cavity’s -3.0 db points from the 0.0 dB reference, divide this bandwidth figure by the resonant frequency and then invert that number to get the loaded Q-Factor

Interesting. That is not how Q is usually measured. There is a formula for calculating the bandwith of a filter:

F(bw) = F0/Q where F0 = the frequency the filter is tuned for and F(bw) = the bandwidth of the filter

This is not how Q is measured although it does result in a close approximation. Example: I purchased a 4-pole filter from K&L in 1996 to help mitigate an interference problem we had with a TDRSS uplink. It had a passband of 5 MHz @ 2085 MHz. Using this I can calculate the Q = 417. K&L measured the Q = 400. EW method is not very far off; nowhere near as far off as Yang's measurement that was discussed earlier.

Q is defined as:

Q = 2*Pi*(Energy Stored) /(Energy Dissipated per Cycle)

The usual way it is measured is to divide the bandwidth (as defined above) into the full height of the spectral peak. There is a diagram and this method is discussed on the Wikipedia page for Bandwith - Q factor.http://en.wikipedia.org/wiki/Q_factor

That is approx 17 gf. Is a bit over the weight of 2 x US dollar coins. If I put them in your outstretched palm, could you feel the weight? Sure it is not a kg but the level is significant and not what some mosquito produces when it lands on your arm.

Comment away but maybe first do a bit of homework on the reported experimental results from Shawyer and the Chinese.

I don't see any paper or report on an in-depth overview of his experiment, his method, his apparatus, his analysis, and his conclusions based on that. Also, data without any error bars is meaningless. Many of his conclusions are non-sequitur and he makes no attempt at justifying them, such as:

"Comparison of the rates of increase of thrust for the different spring constants, using pulsed input power, gave a clear proof that the thrust was produced by momentum transfer and was not due to any “undefined” spurious effect."

Where exactly is the data that gives such "clear proof" so we can judge for ourselves if his conclusion has any merit, and not simply because Shawyer says so? There are many other background effects that could explain away his anomalous results, but he is not exactly very forthcoming.

There should seem to be a difference between "the results of this experiment appear to break the laws of physics; therefore I won't pursue it" and "the results of this experiment appear to break the laws of physics; therefore no one ought to pursue it." The former is a simple life choice, while the latter doesn't seem very much in line with the spirit of science.

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Secondly, if someone is trying to capitalize on pseudo-science, I feel scientists have a moral responsibility to inform people who otherwise wouldn't understand the underlying science behind a proposed device. Informing is all we can do, and in the end, if they want to throw their money at some fantasy, then that's their choice.

I have an interesting question / thought experiment in need of some input.

Suppose we have a perfectly conducting cylinder and we inject microwaves into the side, at the center of the cylinder. Their momentum propagates equally in both directions and the reflections result in standing waves. At one end of the cylinder, there is a thin layer of water sealed behind glass which is transparent to microwaves. At the other end, there is a perfect reflector. Should there be NET thrust now? Energy is being used to heat the water on one side, while the other side is receiving all of the momentum that is reflected from it.

The answer is, momentum is NOT conserved in dissipative systems. There should be thrust in proportion to the amount of heat that can be absorbed by the water. It's heat capacity is not infinite so eventually the system becomes polarized, until the water is allowed to cool.

@Rodal mentioned making the cavity a one-way street. Another idea would be to make the frustum out of different metals. Having zinc at one end and copper at the other end will form a galvanic cell, but it also forms a crude diode! This makes it more difficult for current to flow in one direction vs the other direction in the frustum, accomplishing that goal. Different metals can also make it more or less dissipative at each end.

Todd

I see a few problems. Water has a high dielectric constant, typically around 80 for lower frequencies anyways, rendering it very relfective, not transparent. But lets say instead lossy-ferrite impregnated carbon fiber like they could use on a stealth aircraft. Yes, assymetrical thrust results and you've got a photon rocket. Shawyer's EM Drive proports to give you the cavity Q, many thousands of times more bang per photon.

There may be a significant problem with an EM Drive implementation, dissapating significant amounts of low-grade, non-incandescent heat in space.

But if heat dissipation isn't allowed, then I would say the systems capacity to dissipate heat has become saturated rather than polarized and inoperable.

As far as dissimilar metals and diodes, I don't think it would help. Then again, after just looking up Peltier effect on Wikipedia and having my brain glaze-over, who knows.

My new paper appeared today on arxiv with the number 1505.06917 in gr-qc section. I attach here a version for this forum and the maple worksheet to work with (I used Maple 18). As you will notice, the effect due to gravity is really small making it ineffective to explain the thrust measurements by NASA, if confirmed. On the other side, it appears rather clear that it is possible, with an interferometer, to observe the space-time geometry inside a cavity, for a given energy density of the electromagnetic field, to deviate from perfect flatness. It would be enough to consider relevant these theoretical computations just for such a result. In this way, it is possible to do measurements to test Einstein's general relativity with a table-top device. This should be considered a possible breakthrough and NASA is the first to have realized this.

My view on all this matter remains somewhat skeptical but I am ready to change my mind if ever some sound repetitions of NASA's experiment will be realized and will go through a peer-reviewed journal. Presently, the error bar and the order of magnitude of the effect compete but the paper by NASA is the best accomplished report on these measurements seen so far. It remains indisputable that the idea to put on a pendulum such a cavity to see if something moves it is a really smart one and never attempted before. This is science rather than an usual "ipse dixit" that a lot of scientists prefer today.

P.S: just change the extension of the Maple worksheet from .txt to .mw.

Based on what I have learned, blasting away with a wide band magnetron into a low Q cavity may be a good option as it really reduces lost/NO thrust from being constantly off resonance with a high Q cavity.

After I read the measurement document, I also thought it wasn't even a well-played and plausable scam. But in my present understanding acceleration or mere vibration is necessary for forces to develop.

Acceleration causes the Q-multiplied energy spectra to spread for separation and sideband filtering. No acceleration, no separation and forces balance so no thrust.

Consequently, if it works and works like I understand, it will have the amazing property of negative-inertial resistance. In one direction, you push (accelerate) it, it pushes back harder. Flip the cone over, push on it and it feels lighter. Since nobody's hand is perfectly still, the cone would feel like its vibrating. The more nervous you are, the more nervous it is

A magnetron can be modeled as a negative-resistance device. A single port oscillator or with a circulator a dual-port amplifier. It will mode-lock in its tuning range. I'll have to think about how to model and simulate the system. Would be nice to have an account at a place with Comsol. Its going to take me a while to learn Meep.

There should seem to be a difference between "the results of this experiment appear to break the laws of physics; therefore I won't pursue it" and "the results of this experiment appear to break the laws of physics; therefore no one ought to pursue it." The former is a simple life choice, while the latter doesn't seem very much in line with the spirit of science.

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Secondly, if someone is trying to capitalize on pseudo-science, I feel scientists have a moral responsibility to inform people who otherwise wouldn't understand the underlying science behind a proposed device. Informing is all we can do, and in the end, if they want to throw their money at some fantasy, then that's their choice.

Did you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know.

There should seem to be a difference between "the results of this experiment appear to break the laws of physics; therefore I won't pursue it" and "the results of this experiment appear to break the laws of physics; therefore no one ought to pursue it." The former is a simple life choice, while the latter doesn't seem very much in line with the spirit of science.

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Secondly, if someone is trying to capitalize on pseudo-science, I feel scientists have a moral responsibility to inform people who otherwise wouldn't understand the underlying science behind a proposed device. Informing is all we can do, and in the end, if they want to throw their money at some fantasy, then that's their choice.

As a tax-paying citizen of the U.S., I have a different perspective. I have a problem with our government not allocating at least a small amount of funding to high-risk high-reward scientific endeavors, including such long-shots as the EM Drive. In my experience--and I've been around awhile--those who nicely fit certain areas of research and experimentation into the convenient "pseudo-scientific" basket are either protecting turf or are innately close-minded. This is particularly true when experimental evidence indicates there might be something interesting happening. There are those who will refuse to gaze into the telescope because it simply does not fit their known models. This is just as true today as it was anciently--and the stakes are probably just as high or higher.

Got up from falling asleep during a bad movie tonight and in my dream I'd built an EM Drive. What I found interesting is I put it in my chilled water hot tub. I laughed at the idea when I woke up but thinking about it might have some merits. It would be a good heat sink and a good way to measure thrust by water displacement or weight. Although you really need to find something other than a hot tub.Shell

There should seem to be a difference between "the results of this experiment appear to break the laws of physics; therefore I won't pursue it" and "the results of this experiment appear to break the laws of physics; therefore no one ought to pursue it." The former is a simple life choice, while the latter doesn't seem very much in line with the spirit of science.

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Secondly, if someone is trying to capitalize on pseudo-science, I feel scientists have a moral responsibility to inform people who otherwise wouldn't understand the underlying science behind a proposed device. Informing is all we can do, and in the end, if they want to throw their money at some fantasy, then that's their choice.

As a tax-paying citizen of the U.S., I have a different perspective. I have a problem with our government not allocating at least a small amount of funding to high-risk high-reward scientific endeavors, including such long-shots as the EM Drive. In my experience--and I've been around awhile--those who nicely fit certain areas of research and experimentation into the convenient "pseudo-scientific" basket are either protecting turf or are innately close-minded. This is particularly true when experimental evidence indicates there might be something interesting happening. There are those who will refuse to gaze into the telescope because it simply does not fit their known models. This is just as true today as it was anciently--and the stakes are probably just as high or higher.

Fact is, humans are no different from any other kind of animal. They instinctively protect their turf. While being mandatory to do so in free nature, I think this intrinsic behavior tends to generally hinder 'progress' in our complex societies. That in itself does not say whether the hindered 'progress' would improve conditions for the average populace or worsen them. 'Progress' can also mean you're standing on the edge of a cliff and make one more step forward.. . Or you could make 'progress' by further reducing civil rights and freedoms. It's complicated .

Relating to the argument about tax payer's money.. let's just appreciate the fact that the U.S. is willing to spend around 600 billion USD each year just for military - all tax payer's money. Could a tiny, tiny fraction of that insane amount of money be better spent on things like infrastructure, education and health? I think so. But I'm no american tax payer.. so what do I know :p . Maybe using a couple 10k USD for EM-drive research is too much for the poor tax payer, who already has to pony up ~600 billion USD each year for military. Oh well. Priorities.

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Did you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know.

Clearly many people are persuaded by the argument from authority on this subject because few have the technical skills required to evaluate the speculative theories proposed for the emdrive data. This is why convincing other posters one way or the other on whether the experimental effect exists is so difficult; the question is less about the data and more about what sources of information we trust.

While I am highly skeptical of the thrust data, which seems to suffer from experimental ambiguity and a very low signal-to-noise ratio, personal experience has taught me that the most interesting discoveries in science are rarely found where we expect to see them. Revolutions in science mostly come from serindipity; even if this work shows that efficient propellantless propulsion is a theoretical illusion, it is looking for measurable effects far from where most experimental eyes are focused. Perhaps if those working on the emdrive look intently enough, they will see something nobody expected.

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Did you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know.

Clearly many people are persuaded by the argument from authority on this subject because few have the technical skills required to evaluate the speculative theories proposed for the emdrive data. This is why convincing other posters one way or the other on whether the experimental effect exists is so difficult; the question is less about the data and more about what sources of information we trust.

While I am highly skeptical of the thrust data, which seems to suffer from experimental ambiguity and a very low signal-to-noise ratio, personal experience has taught me that the most interesting discoveries in science are rarely found where we expect to see them. Revolutions in science mostly come from serindipity; even if this work shows that efficient propellantless propulsion is a theoretical illusion, it is looking for measurable effects far from where most experimental eyes are focused. Perhaps if those working on the emdrive look intently enough, they will see something nobody expected.

Discovery is a learning process and we all are learning here. I don't know what I'm seeing in the EM Cavity but I believe there has been enough empirical data generated from widely different test beds that it deserves a time of controlled testing with a highly accredited lab.The scientists and engineers at NASA, a couple universities and a few individuals are doing just that through rigorous testing and documentation.I think there is something there we don't understand and I have no doubt we will find out the why and for me personally I hope it's good news.

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Did you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know.

Clearly many people are persuaded by the argument from authority on this subject because few have the technical skills required to evaluate the speculative theories proposed for the emdrive data. This is why convincing other posters one way or the other on whether the experimental effect exists is so difficult; the question is less about the data and more about what sources of information we trust.

While I am highly skeptical of the thrust data, which seems to suffer from experimental ambiguity and a very low signal-to-noise ratio, personal experience has taught me that the most interesting discoveries in science are rarely found where we expect to see them. Revolutions in science mostly come from serindipity; even if this work shows that efficient propellantless propulsion is a theoretical illusion, it is looking for measurable effects far from where most experimental eyes are focused. Perhaps if those working on the emdrive look intently enough, they will see something nobody expected.

My view is it may well turn out to be nothing but if we did miss something revolutionary because of institutional inertia then it would be unforgivable.

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Did you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know.

Clearly many people are persuaded by the argument from authority on this subject because few have the technical skills required to evaluate the speculative theories proposed for the emdrive data. This is why convincing other posters one way or the other on whether the experimental effect exists is so difficult; the question is less about the data and more about what sources of information we trust.

While I am highly skeptical of the thrust data, which seems to suffer from experimental ambiguity and a very low signal-to-noise ratio, personal experience has taught me that the most interesting discoveries in science are rarely found where we expect to see them. Revolutions in science mostly come from serindipity; even if this work shows that efficient propellantless propulsion is a theoretical illusion, it is looking for measurable effects far from where most experimental eyes are focused. Perhaps if those working on the emdrive look intently enough, they will see something nobody expected.

My view is it may well turn out to be nothing but if we did miss something revolutionary because of institutional inertia then it would be unforgivable.

Actually, the next bigger asteroid impact out of the blue might kill most complex lifeforms on this planet, including humans. I read that a big extinction sized impact is statistically overdue for a couple millions of years now. If we as a species don't even try to come up with something that allows easy leaving of this world's gravity well, we're dead meat. There's no way to tell for sure right now if things like propellantless space drives and warp fields are engineerable in this universe. But not even trying, knowing the factual danger of life being eradicated by a big chunk of rock from the solar system, also knowing such an event is more or less overdue, would be a sin that would be punished by death. We better get our obese asses up and do something to solve this problem.

My 2 cents

P.S.: At least Elon Musk with his SpaceX company has realized the importance of having a backup of humanity and life in other places than Earth. We can only hope, that at least his company's efforts of creating a 10x..100x reusable rocket system comes to full fruition with all the enormous cost reductions. Even without EM-drives and warp field tech, there would then be a least a chance for backing up our civilization.

There was no on-board propellant consumption: http://www.k.u-tokyo.ac.jp/news/20100105press-e.html but Thrust was generated through the explosive expansion of the atmospheric air by microwave energy deposition at the focus of the microwave beam ( the air is heated up to 10,000 degrees Celsius very rapidly. Steady thrust can be generated by repetitively pulsed microwave irradiations.).

So, it wouldn't generate that amount of thrust force without atmospheric air .

Fact is, humans are no different from any other kind of animal. They instinctively protect their turf. While being mandatory to do so in free nature, I think this intrinsic behavior tends to generally hinder 'progress' in our complex societies. That in itself does not say whether the hindered 'progress' would improve conditions for the average populace or worsen them. 'Progress' can also mean you're standing on the edge of a cliff and make one more step forward.. . Or you could make 'progress' by further reducing civil rights and freedoms. It's complicated .

Relating to the argument about tax payer's money.. let's just appreciate the fact that the U.S. is willing to spend around 600 billion USD each year just for military - all tax payer's money. Could a tiny, tiny fraction of that insane amount of money be better spent on things like infrastructure, education and health? I think so. But I'm no american tax payer.. so what do I know :p . Maybe using a couple 10k USD for EM-drive research is too much for the poor tax payer, who already has to pony up ~600 billion USD each year for military. Oh well. Priorities.

I was about to bring up exactly the same thing, but you were faster in putting it down..

I think the majority of the people involved inhere ARE aware that this might turn out to be "bogus science" and remain skeptical, but at the same time there is the perception, based upon a few (questionable, i agree on that) tests/experiments, that there is indeed something going on. That perception alone should be enough to investigate it more in depth, both on the theoretical level as with experiments.

If it turns out to be nothing, well we can all move on to the next interesting thing.. that is what research is all about, no?I do not see the point of waving a warning finger about how not to precede with this because it is all pseudo science. Considering the intellectual capacity demonstrated by individuals inhere, i do not doubt one moment that everybody remains skeptical. Yet the prospect of participating or sitting on the front row of what might be a new area in space exploration remains very exciting...

It is good to have opposing ideas and clashing visions, on condition you keep listening to each other and do not entrench in ideology wars. The thesis/anti thesis/synthesis principle usually yields good results and must say is one of the greatest achievements of this topic. This open source internet collaboration is really one of the finest examples of scientific and engineering collaboration, because with some small exceptions the collaboration stays polite and constructive.

Dismissing curiosity or suppressing the intention to investigate something odd, based upon notion that it should not be possible, well - let me use some strong words here - I find that a form of scientific fundamentalism.

EM Drive under siege. Nothing less than Sean Carroll with this post. In the comment area there is Steven Docker "explaining" why thrust is measured but this does not seem to apply to measures in vacuum by NASA. Don't give up.